Cord blood procalcitonin and Interleukin-6 are highly sensitive and specific in the prediction of early-onset sepsis in preterm infants

Predictive factors for perinatal bacterial transmission from colonized mothers to delivered very-low-birth-weight infants: a retrospective cohort study

This study investigated the predictive factors for perinatal bacterial transmission in very-low-birth-weight infants (VLBWIs) born to mothers with a history of intrapartum colonization. We retrospectively reviewed the medical records of 173 VLBWIs, wherein pathogens were confirmed in maternal cultures obtained from the blood, urine, and vagina during the intrapartum period from 2013 to 2020. Newborns were categorized based on microbiological tests, including gastric aspirates, endotracheal aspirates, blood, and skin/nasal swab cultures collected immediately after birth. Infants whose cultures matched their maternal pathogens were categorized into the "transmission group" (n = 45), while those who tested negative were assigned to the "control group" (n = 128). The predominant maternal-colonizing pathogen observed was Escherichia coli (30.6%), which also emerged as the primary colonizing pathogen in neonates (35.6%). Transmission group had higher incidences of maternal leukocytosis, chorioamnionitis, and cervical cerclage. Regarding neonatal characteristics, the transmission group demonstrated lower initial base excesses (- 6.3 ± 3.9 vs. - 9.2 ± 4.9, P < 0.05) and higher C-reactive protein levels (0.1 ± 0.3 vs. 0.4 ± 0.8, P < 0.05). Notably, regarding major neonatal outcomes, transmission group had higher mortality rates and incidences of severe intraventricular hemorrhage. These findings may be useful for making decisions when considering antibiotic treatment for infants with a history of maternal colonization.

Early procalcitonin assays may reduce antibiotic exposure in premature newborn infants

AIM

The diagnosis of early-onset neonatal sepsis (EOS) remains difficult. The main aim was to study the effect of a new algorithm for EOS, which includes the level of procalcitonin in umbilical cord blood, on the exposure to antibiotic therapy of premature newborn infants.

METHODS

This was a monocentric, observational and retrospective study with before-and-after design. The duration and dose of antibiotic therapy provided as well as the morbidity and mortality were compared in two groups, one included 01 May 2015-30 November 2015 when procalcitonin was not used, and one after the change 01 November 2016-30 May 2017 when procalcitonin was used in a hospital setting in Nice, France.

RESULTS

Sixty newborn infants were included in the before group and 54 in the after group. Antibiotic therapy was stopped after 24 h for 18 newborn infants in the after group and four in the before group, and after 48 h for 26 newborn infants in the after group and 10 in the before group.

CONCLUSION

The implementation of a new decision-making algorithm including early procalcitonin assay of premature newborn infants significantly reduced exposure to antibiotics without modifying mortality or morbidity.

Diagnostic Utility of Interleukin-6 in Early-Onset Sepsis among Term Newborns: Impact of Maternal Risk Factors and CRP Evaluation

(1) Background: Interleukin-6 (IL-6) levels act as an early infection marker preceding C-reactive protein (CRP) elevation. This study seeks to analyze IL-6 behavior in suspected early-onset sepsis (EOS) cases among term newborns, comparing it to that of CRP and evaluating IL-6's diagnostic utility. We also aim to assess the impact of maternal risk factors on EOS in term newborns, quantifying their influence for informed decision making. (2) Methods: The retrospective data analysis included 533 term newborns who were admitted to our hospital because of suspected EOS. IL-6, CRP, and the impact of maternal risk factors were analyzed in the context of EOS using binomial test, Chi-squared test, logistic and linear regression. (3) Results: In the cases of EOS, both IL-6 and CRP were elevated. The increase in CRP can be predicted by the initial increase in IL-6 levels. Among the assessed risk factors, intrapartum maternal fever (adjusted odds ratio 18.1; 95% CI (1.7-4.1)) was identified as the only risk factor significantly associated with EOS. (4) Conclusions: Employing IL-6 as an early infection marker enhanced EOS diagnostic precision due to its detectable early rise. However, caution is required, as elevations in IL-6 and CRP levels do not exclusively indicate EOS. Increased CRP levels in healthy newborns with maternal risk factors may be attributed to dynamics of vaginal labor.

Biomarkers of Neonatal Sepsis: Where We Are and Where We Are Going

Neonatal sepsis is a bacterial bloodstream infection leading to severe clinical manifestations frequently associated with death or irreversible long-term deficits. Antibiotics are the drug of choice to treat sepsis, regardless of age. In neonates, the lack of reliable criteria for a definite diagnosis and the supposition that an early antibiotic administration could reduce sepsis development in children at risk have led to a relevant antibiotic overuse for both prevention and therapy. The availability of biomarkers of neonatal sepsis that could alert the physician to an early diagnosis of neonatal sepsis could improve the short and long-term outcomes of true sepsis cases and reduce the indiscriminate and deleterious use of preventive antibiotics. The main aim of this narrative review is to summarize the main results in this regard and to detail the accuracy of currently used biomarkers for the early diagnosis of neonatal sepsis. Literature analysis showed that, despite intense research, the diagnosis of neonatal sepsis and the conduct of antibiotic therapy cannot be at present decided on the basis of a single biomarker. Given the importance of the problem and the need to reduce the abuse of antibiotics, further studies are urgently required. However, instead of looking for new biomarkers, it seems easier and more productive to test combinations of two or more of the presently available biomarkers. Moreover, studies based on omics technologies should be strongly boosted. However, while waiting for new information, the use of the clinical scores prepared by some scientific institutions could be suggested. Based on maternal risk factors and infant clinical indicators, sepsis risk can be calculated, and a significant reduction in antibiotic consumption can be obtained.

Diagnosis of Neonatal Sepsis: The Role of Inflammatory Markers

This is a narrative review on the role of biomarkers in the diagnosis of neonatal sepsis. We describe the difficulties to obtain standardized definitions in neonatal sepsis and discuss the limitations of published evidence of cut-off values and their sensitivities and specificities. Maternal risk factors influence the results of inflammatory markers as do gestational age, the time of sampling, the use of either cord blood or neonatal peripheral blood, and some non-infectious causes. Current evidence suggests that the use of promising diagnostic markers such as CD11b, CD64, IL-6, IL-8, PCT, and CRP, either alone or in combination, might enable clinicians discontinuing antibiotics confidently within 24-48 h. However, none of the current diagnostic markers is sensitive and specific enough to support the decision of withholding antibiotic treatment without considering clinical findings. It therefore seems to be justified that antibiotics are often initiated in ill term and especially preterm infants. Early markers like IL-6 and later markers like CRP are helpful in the diagnosis of neonatal sepsis considering the clinical aspect of the neonate, the gestational age, maternal risk factors and the time (age of the neonate regarding early-onset sepsis) of blood sampling.

Reliability of Interleukin-6 Alone and in Combination for Diagnosis of Early Onset Neonatal Sepsis: Systematic Review

Neonatal sepsis is a major cause of morbidity and mortality in both preterm and term infants. Early-onset neonatal sepsis (EONS) presents within the first 72 h of life. Diagnosis is difficult as signs and symptoms are non-specific, and inflammatory markers are widely used to confirm or rule out neonatal sepsis. Interleukin-6 (IL-6) is part of the fetal inflammatory response syndrome (FIRS) and therefore an interesting early marker for neonatal sepsis. The main objective for this review was to assess the diagnostic potential of IL-6, alone and in combination, for diagnosis of early neonatal sepsis (EONS) in term and preterm infants, in cord and peripheral blood, and in dependence of timing of sample collection. IL-6 diagnostic accuracy studies for diagnosing EONS published between 1990 and 2020 were retrieved using the PubMed database. We included 31 out of 204 articles evaluating the potential of IL-6 for the diagnosis of EONS in a study population of newborns with culture-proven and/or clinically suspected sepsis. We excluded articles dealing with neonatal bacterial infections other than sepsis and biomarkers other than inflammatory markers, those written in languages other than English or German, studies that did not distinguish between EONS and late-onset sepsis, and animal and in vitro studies. Full-text articles were checked for other relevant studies according to the PRISMA criteria. We identified 31 studies on IL-6 diagnostic accuracy for EONS diagnosis between 1990 and 2020 including a total of 3,276 infants. Sensitivity and specificity were reported, and subgroup analysis was performed. A STARD checklist adapted for neonates with neonatal sepsis was used for quality assessment. The range of IL-6 sensitivity and specificity in neonatal samples was 42.1-100% and 43-100%; the median values were 83 and 83.3%, respectively. IL-6 accuracy was better in preterm infants than in mixed-study populations. Early sample collection at the time of sepsis suspicion had the highest sensitivity when compared to other time points. Cord blood IL-6 had higher diagnostic value compared to peripheral blood. The biomarker combination of IL-6 and CRP was found to be highly sensitive, but poorly specific. Limitations of this review include use of only one database and inclusion of a heterogeneous group of studies and a small number of studies looking at biomarker combinations; a strength of this review is its focus on early-onset sepsis, since type of sepsis was identified as a significant source of heterogeneity in IL-6 diagnostic accuracy studies. We concluded that IL-6 has a good performance as an early diagnostic marker of EONS within a study population of preterm infants, with best results for cord blood IL-6 using cutoff values above 30 pg/ml.

Umbilical Cord Procalcitonin to Detect Early-Onset Sepsis in Newborns: A Promising Biomarker

Background: Up to 7% of neonates born in high-income countries receive antibiotics for suspected early-onset sepsis (EOS). Culture-proven neonatal sepsis has a prevalence of 0.2%, suggesting considerable overtreatment. We studied the diagnostic accuracy of umbilical cord blood and infant blood procalcitonin (PCT) in diagnosing EOS to improve antibiotic stewardship. Methods: Umbilical cord blood PCT was tested in newborns ≥ 32 weeks of gestation. Groups were defined as following: A) culture-proven or probable EOS (n = 25); B) Possible EOS, based on risk factors for which antibiotics were administered for <72 h (n = 49); C) Risk factor(s) for EOS without need for antibiotic treatment (n = 181); D) Healthy controls (n = 74). Additionally, venous or capillary blood PCT and C-reactive protein (CRP) were tested if blood drawing was necessary for standard care. Results: Between June 2019 and March 2021, 329 newborns were included. Umbilical cord blood PCT was significantly higher in group A than in group C and D. No difference between venous or arterial samples was found. Sensitivity and specificity for cord blood procalcitonin were 83 and 62%, respectively (cut-off 0.1 ng/mL). Antepartum maternal antibiotic administration was associated with decreased PCT levels in both cord blood and infant blood directly postpartum in all groups combined. Conclusion: Umbilical cord blood PCT levels are increased in newborns ≥32 weeks with a proven or probable EOS and low in newborns with risk factors for infection, but PCT seems not a reliable marker after maternal antibiotic treatment. PCT could be useful to distinguish infected from healthy newborns with or without EOS risk factors.

T cell cytokines in the diagnostic of early-onset sepsis

BACKGROUND

Early-onset sepsis (EOS) remains a substantial cause of morbidity and mortality among neonates. Yet, currently available biological parameters have not proven to be accurate enough to predict EOS reliably. This study aimed to determine serum concentrations of 13 cytokines in umbilical cord blood and evaluate their diagnostic value for EOS.

METHODS

A prospective single-center study that included analysis of umbilical cord blood of term and preterm neonates who were born from March 2017 to November 2017. Using ELISA analysis, 13 cytokines were simultaneously quantified and correlated with the development of EOS.

RESULTS

Four hundred and seventy-four neonates were included, of which seven met the criteria for culture-positive EOS. Interleukin (IL)-6 (p < 0.001), IL-9 (p = 0.003), and IL-21 (p < 0.001) were significantly increased in neonates with EOS compared to controls. Sensitivity and specificity for IL-6, IL-9, and IL-21 at the defined cut-off points were 85.7 and 77.3%, 71.4 and 62.5%, and 71.4 and 52.0%, respectively.

CONCLUSIONS

In neonates with EOS, IL-9 and IL-21 are significantly elevated and may be employed in the diagnostic of EOS. However, diagnostic accuracy remains lower than with IL-6. Values of 13 T cell cytokines may be used as reference values for future studies in neonates.

IMPACT

Interleukin-9 (IL-9) and interleukin-21 (IL-21) are significantly elevated in neonates with early-onset sepsis. IL-9 and IL-21 have been shown to play a specific role in neonatal sepsis. Neonatal reference values were generated for several cytokines. IL-9 and IL-21 might be attractive biomarkers for neonatal sepsis in future. This study is likely to promote further research in this area. Values of several T cell cytokines may be used as reference values for future studies in neonates.

Imbalance between inflammatory and regulatory cord blood B cells following pre-term birth

Preterm birth (PTB) is one of the most frequent pregnancy complications. It affects millions of babies each year worldwide and is associated with increased morbidity and mortality. PTB-associated alterations in the maternal immune response may have a direct effect on the developing fetal immune system. Having recently shown that B regulatory (Breg) cells are decreased in number and functionally impaired in maternal blood from women delivering preterm, we now addressed the question whether the adaptive immune system is also altered in cord blood (CB) after the onset of PTB. PTB was associated with increased concentrations of IL-6, TNF-α and IL-21 in CB and enhanced IL-6, but decreased IFN-γ and IL-4 in amniotic fluid (AF) samples compared to term delivery (TD). We found no differences in the frequency of CD19 + B cells, CD4 + T cells or CD4+Foxp3+CD25+ T regulatory (Treg) cells in CB cells in PTB vs TD. The frequency of CD86 + B cells was increased, while the percentage of CD24^hiCD38^hiCD19 + Breg and CD1d^hiCD5+ Breg cells and the ability of B cells to convert into Breg cells was diminished in PTB compared to TD. CB B cells from PTB secreted more IL-6, TNF-α, IL-9 and IL-2 compared to B cells obtained from term samples. We conclude that, after PTB onset, a shift from immunoregulation towards inflammation takes place in CB cells that are reportedly representative of the fetal compartment. B cells have a substantial contribution herein. This phenomenon might account for the observed enhanced mortality and morbidity in prematurely born infants. Further studies will clarify how to employ this easy-to-obtain information for closely monitoring newborns at risk.

Procalcitonin in Preterm Neonates: A Different Threshold and Prolonged Interpretation

Objectives: To evaluate the positive threshold of PCT for neonates of <32 weeks of gestation for the diagnosis of early-onset sepsis and to determine if the level of PCT collected within 6 h of life could be used. Design: Retrospective and bicentric study from May 2016 to April 2018. Setting: Two groups were established, neonates evaluated for PCT at birth (CordPCT) and within 6 h of life (delPCT). Patients: Two hundred and sixty neonates of <32 weeks of gestation born in Nice and South Paris (Bicêtre) University Hospitals, had been evaluated for PCT level. Main Outcomes Measures: The value of the PCT positive threshold was determined for the total population and each groups thanks ROC curves. Results: The threshold level of PCT for the total population was 0.98 ng/mL. The threshold value of cordPCT group was 1.00 vs. 0.98 ng/mL for delPCT group. The area under the Receiver Operating Characteristics curve for PCT sampled in delPCT group was significantly higher than in cordPCT group (0.94 compared to 0.75). Conclusions: The threshold level of PCT was higher in this cohort of neonates of <32 weeks of gestation compared to the value generally described for term neonates. The secondary sampling PCT level seems to be usable in screening algorithm for early-onset neonatal sepsis.

Role of SOCS3 in enhanced acute-phase protein genes by neonatal macrophages in response to IL-6

BACKGROUND

Interleukin 6 (IL-6) induce the inflammatory response directly related with the morbidity and mortality of neonatal. Here we aimed to explore the mechanism of IL-6 in neonatal inflammatory response by studying the IL-6/STAT3 signaling pathway.

METHODS

Cord blood samples from health term neonatal and peripheral venous blood from health volunteers were collected. The monocytes of adults and cord blood were isolated and induced into macrophages. Then the macrophages were pretreated with or without MG132 before IL-6 stimulation. Proteins were analyzed by Western blot, mRNA by real time PCR and membrane molecule by flow cytometry.

RESULTS

The acute phase protein gene expression in neonatal macrophages after stimulated with IL-6 were higher than that in adult. Significantly enhanced phosphorylation of STAT3 was seen in neonatal macrophages. Both mRNA and protein expression of SOCS3 in neonatal macrophages were lower than that in adult. After pretreated with MG132, the expression of SOCS3 protein was increased which lead to attenuate the STAT3 phosphorylation and APP gene expression.

CONCLUSION

Neonatal exhibit an enhanced expression of downstream target genes and IL-6/STAT3 signal pathway which is related with the diminished SOCS3. This provides a new sight into inflammatory responses in neonatal.

Diagnostic accuracy of interleukin-6 for early-onset sepsis in preterm neonates

Background: Early-onset sepsis (EOS) is a leading cause of morbidity and mortality among neonates. Yet, accurate diagnosis remains a major challenge in clinical routine.Objective: The aim of this study was to evaluate the diagnostic accuracy of Interleukin-6 (IL-6) in combination with other objective perinatal data for early-onset sepsis (EOS) in preterm neonates.Methods: We conducted a retrospective nested case-control study with preterm neonates with a birth weight < 2000 g born in our NICU between January 2007 and June 2016. Differences of IL-6 levels and other perinatal clinical and laboratory data between neonates with and without EOS were statistically analyzed.Results: Sixty-seven preterm infants with and 115 neonates without EOS were included in this study. Specificity and sensitivity for IL-6 were 72.8% and 75.0%, respectively, with an area under the curve of 0.804 at a cut-off point of 40 ng/l. Depending on the statistical method applied, combining IL-6 with a second perinatal factor led either to an increase of specificity (82.4-100%) or sensitivity (75.0-92.2%).Conclusion: The combination of IL-6 with other perinatal factors can significantly increase specificity and sensitivity in the diagnosis of EOS. However, overall diagnostic accuracy cannot be notably improved as there is a tradeoff between sensitivity and specificity. Although these findings do not necessarily apply in clinical routine, they can be of substantial value in the assistance of individual decision making.

Regulatory role of miRNA-26a in neonatal sepsis

The present study aimed to investigate the expression of microRNA (miRNA) 26a in blood mononuclear cells and serum in neonatal sepsis, as well as its role in the disease pathogenesis. In total 28 cases of neonatal sepsis were included in the study. The mRNA expression levels of miRNA-26a and interleukin (IL)-6 in the blood mononuclear cells and serum samples were detected by reverse transcription-quantitative polymerase chain reaction. The protein expression of IL-6 was detected by western blot analysis and ELISA. The in vitro septic environment was simulated by lipopolysaccharide (LPS) in THP-1 cells, and the expression of miRNA-26a and IL-6 were determined. Interaction between miRNA-26a and IL-6 was confirmed by a dual-luciferase reporter assay. Compared with the control group, the mRNA and protein expression levels of IL-6 in the blood mononuclear cells and serum samples from the neonates with sepsis were significantly elevated, while the expression of miRNA-26a was significantly decreased. In addition, similar results were observed in the LPS-induced septic models in THP-1 cells. Furthermore, the results of the dual-luciferase reporter assay demonstrated that IL-6 was the direct target of miRNA-26a. The expression of IL-6 was significantly upregulated in the blood mononuclear cells and serum in neonatal sepsis, which may be associated with the downregulation of miRNA-26a. miRNA-26a may regulate the disease pathogenesis and immune responses.

The role of nCD64 in the diagnosis of neonatal sepsis in preterm newborns

BACKGROUND

Diagnosing neonatal sepsis is difficult, particularly in preterm newborns. A promising method appears to be evaluation of cell surface markers by flow cytometry.

METHODS

This prospective study investigated 217 newborns suspected of having early- or late-onset neonatal sepsis. In all, flow cytometry was used to determine the proportion of CD64-positive neutrophils (nCD64). Based on the clinical course and laboratory test results, newborns were categorized as having proven, possible, clinical or no neonatal sepsis. Subsequently, associations between the categories and nCD64 values were analyzed.

RESULTS

There were significant associations between nCD64 values and the development of sepsis in newborns with both early- or late-onset sepsis.

CONCLUSION

nCD64expression is significantly elevated in preterm newborn with early and late onset sepsis. The results show that nCD64 is a reliable marker for diagnosing neonatal sepsis.

Role of Zc3h12a in enhanced IL-6 production by newborn mononuclear cells in response to lipopolysaccharide

BACKGROUND

The uncontrolled inflammatory response following infection is closely related to the morbidity and mortality of neonates. Interleukin 6 (IL-6) plays an important role in the pathogenesis and prognosis of this process. To better elucidate the secretion of IL-6 following infection in neonates, we investigated the IL-6 level and mechanism of IL-6/TLR4 signaling pathways.

METHODS

We compared the IL-6, procalcitonin (PCT), and CRP levels between septic neonates and toddlers. In vitro cord blood samples from healthy term neonates and peripheral venous blood from healthy adult volunteers were collected. Protein expression was analyzed by Western blotting, mRNA expression by real-time PCR and membrane molecule expression by flow cytometry.

RESULTS

The IL-6 concentrations were significantly higher in the neonate group than in the toddler group (p < 0.05). In the toddler group, the IL-6 concentrations were correlated positively with both PCT and CRP (PCT: r = 0.451, p = 0.001; CRP: r = 0.243, p = 0.023). In vitro, the secretion of IL-6 increased with the rising concentrations of LPS; at 1000 ng/ml LPS, IL-6 secretion from the monocytes of neonates was significantly higher than that of adults. There was a marked decreased level of MyD88 in neonate monocytes compared with that in adult monocytes. Additionally, the mRNA levels of Zc3h12a in neonate monocytes were significantly lower than those in adult monocytes following LPS stimulation.

CONCLUSION

Neonates displayed enhanced IL-6 production after infection. Our study, for the first time, reported a significant decrease in the expression of Zc3h12a in neonates. Thus, Zc3h12a may be a key factor for the aberrant increase in IL-6 after neonate infection.

Intrauterine inflammation, infection, or both (Triple I): A new concept for chorioamnionitis

Chorioamnionitis is a common cause of preterm birth and may cause adverse neonatal outcomes, including neurodevelopmental sequelae. Chorioamnionitis has been marked to a heterogeneous setting of conditions characterized by infection or inflammation or both, followed by a great variety in clinical practice for mothers and their newborns. Recently, a descriptive term: "intrauterine inflammation or infection or both" abbreviated as "Triple I" has been proposed by a National Institute of Child Health and Human Development expert panel to replace the term chorioamnionitis. It is particularly important to recognize that an isolated maternal fever does not automatically equate to chorioamnionitis. This article will review the current literature on chorioamnionitis, and introduce the concept of Triple I, as well as recommendations for assessment and management of pregnant women and their newborns with a diagnosis of Triple I.

Evaluation and Management of Women and Newborns With a Maternal Diagnosis of Chorioamnionitis: Summary of a Workshop

In January 2015, the Eunice Kennedy Shriver National Institute of Child Health and Human Development invited an expert panel to a workshop to address numerous knowledge gaps and to provide evidence-based guidelines for the diagnosis and management of pregnant women with what had been commonly called chorioamnionitis and the neonates born to these women. The panel noted that the term chorioamnionitis has been used to label a heterogeneous array of conditions characterized by infection and inflammation or both with a consequent great variation in clinical practice for mothers and their newborns. Therefore, the panel proposed to replace the term chorioamnionitis with a more general, descriptive term: "intrauterine inflammation or infection or both," abbreviated as "Triple I." The panel proposed a classification for Triple I and recommended approaches to evaluation and management of pregnant women and their newborns with a diagnosis of Triple I. It is particularly important to recognize that an isolated maternal fever is not synonymous with chorioamnionitis. A research agenda was proposed to further refine the definition and management of this complex group of conditions. This article provides a summary of the workshop presentations and discussions.

Early-Onset Neonatal Sepsis: Still Room for Improvement in Procalcitonin Diagnostic Accuracy Studies

To perform a systematic review assessing accuracy and completeness of diagnostic studies of procalcitonin (PCT) for early-onset neonatal sepsis (EONS) using the Standards for Reporting of Diagnostic Accuracy (STARD) initiative.EONS, diagnosed during the first 3 days of life, remains a common and serious problem. Increased PCT is a potentially useful diagnostic marker of EONS, but reports in the literature are contradictory. There are several possible explanations for the divergent results including the quality of studies reporting the clinical usefulness of PCT in ruling in or ruling out EONS.We systematically reviewed PubMed, Scopus, and the Cochrane Library databases up to October 1, 2014. Studies were eligible for inclusion in our review if they provided measures of PCT accuracy for diagnosing EONS. A data extraction form based on the STARD checklist and adapted for neonates with EONS was used to appraise the quality of the reporting of included studies.We found 18 articles (1998-2014) fulfilling our eligibility criteria which were included in the final analysis. Overall, the results of our analysis showed that the quality of studies reporting diagnostic accuracy of PCT for EONS was suboptimal leaving ample room for improvement. Information on key elements of design, analysis, and interpretation of test accuracy were frequently missing.Authors should be aware of the STARD criteria before starting a study in this field. We welcome stricter adherence to this guideline. Well-reported studies with appropriate designs will provide more reliable information to guide decisions on the use and interpretations of PCT test results in the management of neonates with EONS.

Fetal and early neonatal interleukin-6 response

In 1998, a systemic fetal cytokine response, defined as a plasma interleukin-6 (IL-6) value above 11 pg/mL, was reported to be a major independent risk factor for the subsequent development of neonatal morbid events even after adjustments for gestational age and other confounders. Since then, the body of literature investigating the use of blood concentrations of IL-6 as a hallmark of the fetal inflammatory response syndrome (FIRS), a diagnostic marker of early-onset neonatal sepsis (EONS) and a risk predictor of white matter injury (WMI), has grown rapidly. In this article, we critically review: IL-6 biological functions; current evidence on the association between IL-6, preterm birth, FIRS and EONS; IL-6 reference intervals and dynamics in the early neonatal period; IL-6 response during the immediate postnatal period and perinatal confounders; accuracy and completeness of IL-6 diagnostic studies for EONS (according to the Standards for Reporting of Diagnostic Accuracy statement); and recent breakthroughs in the association between fetal blood IL-6, EONS, and WMI.

Interleukin-6 as an early diagnostic marker for bacterial sepsis in patients with liver cirrhosis

OBJECTIVE

Liver cirrhosis is associated with frequent bacterial infections that increase the mortality rate. However, the early diagnosis and treatment of these infections are often difficult. In this retrospective-prospective observational study, the serum levels of interleukin-6 (IL-6) and procalcitonin (PCT) were measured in 233 cirrhotic patients to evaluate the early diagnostic and prognostic values of IL-6 and PCT for cirrhotic patients.

METHODS

Cirrhotic patients admitted to the Liver Research Center of the First Affiliated Hospital of Fujian Medical University between 1 October 2012 and 30 June 2014 were enrolled. They showed no evidence of infection on admission, and all had first onset of fever and met the systemic inflammatory response syndrome criteria 72 hours after admission. The serum IL-6 and PCT levels were determined on admission, at the onset of fever (0 hour) and 24 and 48 hours after fever onset.

RESULTS

A total of 233 cirrhotic patients, including 183 men and 50 women, with a median age of 56 (46-65) years were enrolled. A training group of 159 patients was retrospectively enrolled from 1 October 2012 to 31 December 2013, and a validation group of 74 patients was prospectively enrolled from 1 January 2014 to 30 June 2014. Among these patients, 134 were diagnosed with bacterial sepsis, 96 of whom were in the training group and 38 of whom were in the validation group; infections were ultimately ruled out in 99 patients: 63 training patients and 36 validation patients. At 0 hour, the IL-6 and PCT levels as well as the proportion of neutrophils were much higher in septic patients than in nonseptic ones. The IL-6 level and proportion of neutrophils peaked upon the onset of fever, 24 hours before the PCT levels and white blood cell count, and then sharply declined. The area under the receiver operating characteristic curve of IL-6 for diagnosing sepsis was largest at the onset of fever (area under the receiver operating characteristic curve, 0.983; 95% confidence interval, 0.967-0.999). The threshold of IL-6 for diagnosis was 135 pg/mL, with a sensitivity of 94.8% and a specificity of 93.7%. These diagnostic values were also confirmed in the validation group, with a sensitivity of 97.4% and specificity of 80.6%. Eleven (11.5%) patients died, and 85 (88.5%) patients recovered in the sepsis group of training patients after a 4-week follow-up. The IL-6 level was significantly higher in the nonsurvival group than that in the survival group (1813.00 vs 472.10 pg/mL, P = .004) at the onset of sepsis. The cutoff value for predicting prognosis was 1105 pg/mL, with a sensitivity of 81.8% and a specificity of 76.5%.

CONCLUSIONS

The serum IL-6 levels increased earlier than the PCT in septic cirrhotic patients. The direct measurement of the serum IL-6 level can help to rapidly detect bacterial infection, thus allowing for early therapeutic decisions and prognostic predictions.